Design, Synthesis And Properties Of Thiosemicarbazide Schiff Base And Its Complexes

Because of its unique structure, thiosemicarbazide Schiff base are widely used in biological chemistry, catalytic chemistry, analysis chemistry, material chemistry and other fields. Schiff base contains N, S, O and other multiple coordination atoms, which can introduce a variety of groups through reacting with compound containing active carbonyl. Therefore, The formation of thiosemicarbazide Schiff base complexes is flexible. This paper mainly includes the following four parts:（1） The synthesis methods and mechanism of a mino thiourea Schiff base were introduced. The classification, application and research status of thiourea Schiff base were summarized.（2） Four kinds of Schiff base ligands have Synthesised based on 4-phenyl thiosemicarbazide, namely 4-phenyl thiosemicarbazide shrink dimethylamino benzaldehyde hydrazone, 4-phenyl thiosemicarbazide shrink benzophenone hydrazone, 4-（2-pyridinecarbonyl）-1-phenyl thiosemicarbazide, 4-phenyl thiosemicarbazide shrink nitrobenzaldehyde hydrazone. The crystal structure of 4-phenyl thiosemicarbazide shrink dimethylamino benzaldehyde hydrazone and 4-phenyl thiosemicarbazide shrink benzophenone hydrazone have been obtained. The four kinds of the ligand and metal salt react to produce nine complexes by stirring at room temperature or sealed diffusion method. The molecular formula of the 4 ligands and 9 complexes is as follows:[C16H14N4S]（H2L1）（1）[C₂₀H₁₇N3S（H2L2）]（2）[C13H12ON4S]（H2L3）[C14H12O2N4S]（H₂L₄）[Ni(C₁₆H₁₈N4S)2·C2H5OH]（3）[Cu(C₁₆H₁₈N4S)2·C4H5N]（4）[Ni(C₂₀H₁₇N3S)2]（5）[Cd(C₂₀H₁₇N3S)2]（6）[Zn(C₂₀H₁₇N3S)2]（7）[Co(C₂₀H₁₇N3S)2（8）[Ni（C13H12N4OS）2]（9）[Co2（C14H12N4S）（C5H7O2）4·2H2O]（10）[Co（C14H12N4O2S）3·C2H5OH·CH3OH]（11）（3） X-ray single crystal diffraction measurements of 9 kinds of complexes were carried out and their structural characteristics were analyzed. The results show that nine kinds of compounds contain hydrogen bonding and Ï€-Ï€ force. They build a 3D supra molecular structure of the complex thorugh two forces synergies. Because the relationship between the coordination role of the molecular complexes 3 and 4 has better coplanarity. Complex 10 is a dual-core structure, other complexes are mononuclear structure.（4） Complexes were characterized by spectroscopy, thermal spectrum, solid fluorescence, X-ray powder diffraction. IR and XRD results show that the complex structures obtained are right; TG curves show that the thermal stability of the ligand and metal complex have increased in varying degrees; solid fluorescence spectra showed that the four ligands have fluorescent properties, after reacting with the metal ions, fluorescent of metal cobalt, nickel and copper complex become weaker than ligand or occurs fluorescence quenching. But the metal zinc and cadmium complexes have strong fluorescence emission, which can be used as a potential photoactive material.